Apparatus for the production of cellular building materials



Feb. 21, 1928.

G. M. THOMSON APPARATUS FOR THE PRODUCTION OF CELLULAR BUILDING IATERIALS Filed March 18. 1927 GEORGE mum THOM50N INVENTOR ATTGRNEYQ 40 will be later definedinthe'claims.

Patented Feb. 21, 19 2s. v

UNITED STATES 1,660,243 PATENT OFFICE.

GEORGE E. THOMSON, OF CALEDONIA, ONTARIO, CANADA, ASSIGNOR TO :PENNSYI" VANIA GYPSUM COMPANY, OF CHESTER, PENNSYLVANIA, "A CORPORATION OF DELAWARE.

hrrARAI-Usron rim rnonuorron or cnLLuLa'n BUILDING MATERIALS.

Original application fled August 10, 1926, Serial No. 128,504, and in Canada February 22, 1927;- Divided and this application fled March 18, 1927. Serial No. 176,559.

This invention relates to an apparatus for producing cellular or 'porous building or structural material from such substances as gy sum, cements or other. suitable materials,

6 an is a divisionof my application Ser. Nix

128,504, filed Aug. 10, 1926.

It is well known that such cellular materials are adapted to resist the, transference .of heat and sound and are therefore well 1 adapted for certain building requirements.

It is thus an object of this invention to provide a continuous, mechanical process and an apparatus for the economical production of such materials, without the useof the usual chemicals now employed in the proc esses heretofore known.

Anotherobject of the invention is to proensityin a readily contro ed so the individual cells and cell walls are of'substantially uniform dimensions.

A still further and im ortant object of the invention is to provide or the ready control of the ratios involved in connection with the 85 materials employed in the production of porous building materials. I Other objects of the invention will be a parent from the following description of e Invention, the. essential features of whlc Such orous materials have heretofore been pro need, by causing evolution of a gas in the resence of a slurry of plaster of Paris or quic -setting cement, for; example,

use of sulphate of aluminium and cium carbonate. .Moreover, a colloid has been added to the mix to increase the surfaeetension of the bubbles formed in the slurry.

It will be" apparent that, in order to secure desired results in .such recesses, definite control of the evolution 0 gas, with respect to the initial setting of the material and the variable factors involved, is of prime imparatus, orous building'material of reportance, but difiicult to obtain in the commer1cal operation of such processes.

The ultimate strength of laster of Paris or qulck-setting cements, su sequent to hydratlon, setting and drying is dependent, not only on their primary characteristics, but on the am0unt of water, colloid etc. added thereto m the process of production. Water, in

excess of that actually rcquiredin the formation of the crystals, lowers the ultimate strength. The same is true of the colloid added. It will therefore be apparent that, m order to secure a product of the required density with maximum strength, definite,-

ready control of these variable factors is neclessary 1n the production of these mater a s.

The invention and the manner in which its objects are obtained will now be described with reference to the accompanying drawmgs m which:

Figure 1 1s a sectionalelevation of the ap- Figure 2 is a fra enta sectional elevation of a modified f i m, c

Figure 3 is a section through the impeller wheels. I In the drawings 1- is a mixing chamber, having a bottom 2 inclined to the opening 3 leading to an air-mixin chamber 4 through pipe 5. As shown in Figure 2. these two chambers may be connected by means of a pipeor tube 5, in which case the bottom of the mixing chamber would be semi-spherical the vanes of with the exit at the centre. 6 is a perforated artition located just below the feed-openin unto the air mixing chamber 4, 7 a pipe lea ing to the chamber at 'a point below the par-' h tit1on and having a valve. 8, while 9 is a pipe' leading to the chamber above the partition 6 and having a valve 10. A discharge chute 11 leads from the chamber 4.

Hollow conical impeller wheels 12" and 12, 7

having radial blades'or vanes 13 as shown, are mounted on-shafts -14 and14 ournalledin bearings 15. The shafts 14 and 14 are driven by any suitable means with variable speed ulleyls 16 and 16 andare so placed t at w en t ecapparatus is in operatlon, the impeller wheels 12 and. 12 rotatewith n the chambers 1 and 4 respectively. Theimpeller wheels 12 are secured to the shaft 14 in an inverted position relative to'the wheels 12, that is the open end of each .wheel faces downwardly, for a purpose to be defined later.

The dry plaster of Paris or cements in use, with the required water for their hydration are fed into the chamber 1, where the rotating impeller wheels 12 thoroughly mix the material and water and on account of the shape and position of the impeller wheels, the mixture or slurry will flow from chamber 1 to the air mixing chamber 4 at a rate controlled. by the rate of rotation of the wheels. If desired the dry materials may be gauged before introducing the mixture into chamber 1.

The amount of water of so-called normal consistency is a substantially fixed quantity for any particular plaster of Paris or cement and therefore, this ratio varies only with changes in the characteristics of the material used. At this stage in the process water of normal consistency only is added.

The slurry thus flows into chamber 4 at a predetermined constant rate and gas or air is admitted thereto by opening valve 8. The gas is forced through the perforations in partition 6 and flows in substantially slender columns or streams. The amount of gas or air so admitted will be governed by the porosity or density required in the finished product, and regulated by means of the valve 8. a

At the same time colloidalized water, that is water containing a colloid, such as, for example, tannic acid, other organic acids, aldehydes, ketones, saponin sugar, etc. is admitted to chamber 4 by opening valve 10. The water here added is to provide for the formation of gas or air bubbles in the slurry and the colloid is added to increas the surface tension of the bubbles. The water ratio at this point is therefore dependent upon the porosity required in the finished product and the size of the cells to be formed therein. The size of the cells formed is regulated by division of the gas or air admitted to the slurry, to form volumes of the desired size to be surrounded by the colloidalized water to form bubbles. This division of the gas or air to regulate the cell size is effected, by rotation of the impeller wheels 12", whereby the streams or columns of gas are divided into. volumes, which becomes surrounded with films of the colloidalized water forming bubbles. In the upward travel of the slurry and bubbles the latter are subdivided more orless until the last impeller wheel has been passed and the de sired size of bubble has been formed in the slurry. It will be apparent that the rate of travel of the shaft 14*, the number of impeller wheels employed and the number of vanes or blades on the wheels will determine the extent to which the air is subdivided and therefore the size of cells formed in the finished material.

When theslurry, impregnated with bubbles, reaches the discharge opening, it flows down the chute 11 and is shaped and allowed to set in accordance with the use to which the porous material is to be put. 7

From .what has been said, it will be apparent that, since theamount of Water added for bubble formationis directly related to the amount of gas or air introduced into the slurry and since the amount of colloidalizer is related directly to the amount of gas or air introduced, the amount of colloidalizer can be related directly to the amount of water introduced. Therefore, a colloidalized water solution, of predetermined colloid content, can be add-ed to the slurr in direct relation to the amount of gas or a1r introduced, for the purpose of expanding the mass uniformly and producing a porous or cellular mass of predetermined density. I

This invention thus provides for direct mechanical control of the variable factors involved in the production of porous or cellular building materials of a desired density.

The term slurry used in this specification and the claims is intended to define the wet mass of plaster of Paris or quick-setting cement containing water of so-called normal consistency and by water of normal consistency is meant the amount required for hydration of such materials as set forth in standard specifications.

While a specific embodiment of the invention has been described in some detail, it will be obvious that various modifications and changes may be 1nade,'without departing from the spirit or scope of the invention as defined in the following claims. The invention has been described with particular reference to a continuous process, but it is obviously applicable to the so-called batchprocess as well.

While I have described in this application a complete process and the apparatus em ployed for operating it, it is to be noted that claims specific to the important feature, relating to theregulation of the admission of colloid and water, in excess of that of normal consistency, are not embodied herein, but are made the subject of another application filed concurrently herewith.

I claim:

1. Apparatus for the production of porous building materials comprising, in combination, a slurry mixing chamber having an outlet at the bottom, means in said chamber to agitate the slurry and cause a downward flow thereof, a gas mixing chamber connected with the outlet of said chamber having a perforated partition near its bottom, means for admitting gas below said partition, and means for subdividing the volumes of gas passing through the perforations in said partition.

2. Apparatus for the production of porous building materials comprising, in combination, a slurry mixing chamber having an outlet at the bottom, means in said chamber to agitate the slurry and cause a'downward flow thereof, a gas mixing chamber connected with the outlet of said chamber,

having a perforated partition near its bottom, means for admitting gas'below. said partition, and means for subdividing the volumes of gas passing through the perforations ins-aid partition, said last named means comprising hollow, conical impeller Wheels mounted on a shaft adjacent radial openings in said wheels.

3. Apparatus for the product-ion of por ous building materials comprising, in combination, a slurry mlxing chamber .havlng an:

outlet at-the bottom, means in said chamber to agitate theslurry and cause a downward .flow thereof, a gas mixing chamber connected with the outlet of said chamber havdisposed ing a perforated partition near its bottom, means'for admittin gas below said partition, means for subdividing the volumes of gas passing through'the perforations in said partition and means for rotating said agitating means and said gas subdividing means at variable rates. g

4:. Apparatus for the'production of cellular building material comprising a slur?!- V tank adapted to contain material, agitating means liquid and sol d therein adapted to cause a downward flow of the material, a second vtank ada ted to contain a slurry, means to establis communication between the lower portions of said tanks, a sloping bottom in said slurry tank adapted to direct material into said communicating;

means, agitating means in said second tank, said agitating means adapted to cause an upward "flow of material in said tank, a perforated plate disposed in the second defining a gas Inlet below said plate, a water inlet and having radial blades lular buildin material, com

'mitt'ing air a chamber near the bottom thereof,

'ture. above v said plate, and discharge meansatthetopofsaidtank,

direct material .into said communlcating' means, agitating means in said second tank, said agitating means adapted to cause an upward flow of material in said tank, a perforated plate disposed in the second tank defining a chamber near the bottom thereof, a gas inlet below said plate, a water inlet disposed above said plate, discharge means at the top of said tank and means associated with the respective agitating means whereby diiferential speeds may be obtained.

lular building material comprising in combination with a slurry mixing chamber, variable means for admitting to said chamber a variably controlled flow of air in fine .6. Apparatus for the production of (291- streams, means for admitting colloidized water to said chamber and for regulating the admission of said water, means for rogres-- -sively subdividing said streams 0 air to form bubbles and discharge means for said chamber.

7. Apparatus for the production of celrising in comurry mixing c bination, a s

means in sald chamber a discharge opening,

to impel the slurry to'said discharge openvariable means in said-chamber for adto form bubbles in the slu and means completely submerged in the urry for progressively subdivi ing 'said bubbles.

8. Apparatus as defined inclaim? having means 'forvarying thespeed of said submerged means.

In testimony GEORGE M. THOMSON.

5 amber havmg whereof I afiix my signa- 

